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1.
Axial surveys were performed in the two river tributaries of the Cochin estuary, SW India during November 1988. Surficial sediments were subjected to sequential chemical extractions to delineate five metal fractions, namely, exchangeable, carbonate bound, easily reducible, organic/sulfide bound, and residual. The results indicated selective accumulation of Mn and Ni in carbonate bound and organic/sulfide forms, along with marginal amounts of Co in the exchangeable fraction. Large portions of Fe and Cr occurred in the residual fraction, whereas composite fractionation of Zn species was noticed. The exchangeable fractions of Fe and Cr as well as of easily reducible cobalt were below detection limits. The levels of Cr and Zn indicate anthropogenic inputs in this estuary, whereas Co and Ni show regional contamination exceeding natural levels. The analytical speciation procedure helps to deduce the sedimental diagenetic processes in the estuarine environment. 相似文献
2.
The water ecosystem of the Vyshny Volochek Reservoir is characterized based on the study of the distribution of heavy metals speciations in the solid phase and pore waters of bottom sediments. Using the sequential extraction procedure, it is shown that Mn is mainly present in exchangeable and carbonate-bound forms; significant roles for Fe, Zn, Pb, and Co are played by forms that are bound to iron and manganese hydroxides and Cu and Ni are mainly bound to organic matter. Thermodynamic calculations have established the prevailing share of the following forms in pore waters: free ions for Zn, Ni, Co, and Cd, carbonate complexes for Pb, and fulvic complexes for Cu. It has been revealed that the speciation forms of heavy metals in bottom sediments depend on the lithological features and content of organic matter in sediments. 相似文献
3.
The concentrations of N, P and Fe in surface sediments and interstitial and overlying (bottom and surface) waters of the
Ashtamudi estuary located in the southwest coast of India are reported along with the various chemical species of N (NO2–N, NO3–N, NH3–N and total N) and P (organic P, inorganic P and total P) in interstitial and overlying waters and discussed in terms of
the physico-chemical environment of the system. The interstitial water exhibits higher salinity values compared to bottom
and surface waters, indicating the coupled effects of salt-wedge phenomena and gravitational convection of more saline-denser
marine water downward through surface sediments. N, P and Fe as well as their chemical forms are enriched in the interstitial
water compared to bottom and surface waters. However, the dissolved oxygen (DO) shows an opposite trend. The marked enrichment
of NH3–N in the interstitial water and its marginal presence in bottom and surface waters, together with the substantial decrease
in the DO concentrations of bottom water and consequent increase in the concentrations of NO2–N and NO3–N in interstitial and bottom waters, points to the nitrification process operating in the sediment-water interface of the
Ashtamudi estuary. The enrichment of total N, P and Fe in the interstitial water compared to the overlying counterparts and
the positive correlation of sediment N, P and Fe with mud contents as well as organic carbon indicate that these elements
are liberated during the early diagenetic decomposition of organic matter trapped in estuarine muds.
Received: 5 Oktober 1998 · Accepted: 9 February 1999 相似文献
4.
太湖MS岩芯重金属元素地球化学形态研究 总被引：21，自引：4，他引：17
采用BCR三步提取法对太湖MS岩芯沉积物中Cu、Fe、Mn、Ni、Pb和Zn等6种重金属元素的化学形态进行了研究.结果表明,有效结合态的Cu、Ni和Pb主要以有机物及硫化物结合态、Fe-Mn氧化物结合态存在,Fe和Zn主要以Fe-Mn氧化物结合态存在,Mn主要以可交换态及碳酸盐结合态存在;Fe-Mn氧化物结合态的Ni、Pb和Zn与可还原态的Mn有较好的正相关关系,有机物及硫化物结合态的Cu、Mn、Ni、Pb和Zn与有机碳含量有较好的正相关关系;重金属形态分布体现了重金属元素地球化学性质的差异,以及重金属形态含量与沉积物理化性质的关系.沉积岩芯重金属元素形态垂向变化规律及次生相富集系数表明,Cu、Mn、Ni、Pb和Zn在沉积岩芯13～4 cm有效结合态含量较稳定,为自然沉积;4～0 cm有效结合态含量明显升高,存在一定程度的人为污染.根据137Cs测年结果判断,沉积岩芯Cu、Mn、Ni、Pb和Zn等重金属污染开始于20世纪70年代末期,主要污染元素及污染历史与太湖流域污染工业类型及经济发展阶段相吻合. 相似文献
5.
The distribution of dissolved and particle-bound phosphorus (P) was investigated in the Elbe estuary during March 1995. The forms of particulate P were studied with a sequential extraction technique. Organic P dominated particle-bound P in the outer reaches of the estuary (52%), decreased to a minimum of 21% in the turbidity zone, and increased to 33% further upstream. Fe-bound P was the second most important P species in the outer reaches (27%) and dominated in the turbidity zone (up to 57%) and upstream of the turbidity zone (up to 48%). The P:Fe ratio increased with decreasing salinity, from 0.11 in the outer reaches to about 0.22 at zero salinity. Dissolved inorganic P release from reverine suspended matter was about two to three times larger than release, from marine suspended matter and was dominated by release of Fe-bound P. Dissolved inorganic P release from marine and from riverine organic matter were of equal importance. Because marine suspended matter dominates in the estuary, this suggests riverine organic matter is remineralized much faster than marine organic matter. This is in line with the refractory nature of marine organic matter (no phytoplankton bloom) and the easily degradable character of the riverine suspended matter (phytoplankton bloom) in the Elbe estuary during March 1995. 相似文献
6.
7.
太湖沉积物中重金属的地球化学形态及特征分析 总被引：24，自引：2，他引：22
用连续提取法分析了太湖沉积物5种重金属的地球化学形态,对地球化学形态的组成和地理特征进行了分析研究.重金属地球化学形态配分的共同特点是可交换态最低,残渣态最高.两种形态中Cd的可交换态最高,Cr的残渣态最高,可交换态最低.Cd的碳酸盐态较高,Cr的最低;Pb、Cd的Fe-Mn氧化态较高,Cu的偏低;Cu的有机态最高,Cd的最低;Zn的地球化学形态比例大都处于中间.地域上变化较大的元素是Cd和Cu,变化不明显的元素有Pb和Zn.化学成分中Fe2O3、MnO与重金属地球化学形态的相关性最好,TOC与Cu的形态相关系数最高.综合对比分析表明,太湖沉积物重金属的生物有效性以Cd为最高,其次为Pb. 相似文献
8.
基于地统计学和GIS技术的北京市大兴区礼贤镇土壤养分空间变异性研究 总被引：3，自引：0，他引：3
运用地统计学和GIS方法,对北京市大兴区礼贤镇的表层土壤全氮、全磷、全钾、全硼、碱解氮、有效磷、速效钾、有效硼、有机质和pH值等参数的空间变异及分布特征进行了研究。结果表明,研究区内有效磷、速效钾、碱解氮变异系数分别为10599%、10043%、8029%,分异性较强。经过不同趋势阶数指标插值误差的综合比较,初步确定全磷、有效磷、全钾、速效钾、全硼、有效硼应该选择一阶,碱解氮、有机质和pH值应该选择无趋势,而全氮则应该选择二阶。全磷、有效磷、全钾、全硼、pH值的理论模型为指数模型,速效钾、全氮、碱解氮、有效硼、有机质的理论模型为线性模型。全磷、有效磷、全钾、全硼、pH值主要受到结构性因素的影响,全氮、有效硼、有机质受到结构性因素和随机性因素的共同影响,速效钾、碱解氮主要受到随机性因素的影响。通过普通克里格插值图清晰可见,按照含量分布特点土壤中全氮、碱解氮、全磷、有效硼、有机质、有效磷的空间展布相似,全钾和速效钾的空间展布相似,全硼的空间展布特点与其他指标都不相同,这与统计学分析结果具有相似性。通过了解研究区土壤中10项养分指标分布情况,对及时调整肥料用量比,实现有针对性施肥,调整农业结构以及优势农产品规划和布局提供数据支持。 相似文献
9.
Samir M. Nasr Mohamed A. Okbah Wafaa I. El-Anany Naglaa F. Soliman 《Geochemistry International》2018,56(2):182-188
A five step sequential extraction technique, following Tessier’s protocol has been applied to determine the chemical association of aluminium with major sedimentary phases (exchangeable, carbonate, manganese and iron oxides, organic and residual fraction) in four short sediment cores collected from El-Burullus lagoon of the Nile delta, Egypt. This study is a first approach of chemical fractionation of aluminium in one of the protective areas of the Mediterranean Sea of Egypt. The total metal content was also determined. The results of the fractionation study indicated that aluminium was mainly associated with the residual fraction (>95%). The organic and Fe–Mn oxide fractions were the next important phases. The exchangeable and carbonate fractions were less than 1%, limiting its potential toxicity as a pollutant. The geochemical analysis of aluminium forms reflected the lithogenic origin of this metal in the study area. 相似文献
10.
《Applied Geochemistry》1998,13(4):451-462
Water, suspended matter, and sediment samples were taken from 8 locations along the Yangtze River in 1992. The concentration and speciation (exchangeable, bound to carbonates, bound to Fe–Mn oxides, bound to organic matter, and residual forms) of rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) were determined by instrumental neutron activation analysis (INAA).The contents of the soluble fraction of REEs in the river are low, and REEs mainly reside in particulate form. In the particles, the chondrite-normalized distribution patterns show significant LREE enrichment and Eu-depletion. While normalized to shales, both sediments and suspended matter samples show relative LREE enrichment and HREE depletion. REEs are relatively enriched in fine-grained fractions of the sediments.The speciation characteristics of REEs in the sediments and suspended matter are very similar. The amount of the five forms follows the order: residual>>bound to organic matter∼bound to Fe–Mn oxides>bound to carbonates>>exchangeable. About 65 to 85% of REEs in the particles exist in the residual form, and the exchangeable form is very low. High proportions of residual REEs reveal that REEs in sediments and suspended matter are controlled by their abundances in the earth's crust. Carbonate, Fe–Mn oxide and organic fractions of REEs in sediments account for 2.4–6.9%, 5.2–11.1%, and 7.3–14.0% of the total contents respectively. They are similar to those in the suspended matter. This shows that carbonates, Fe–Mn oxides and organic matter play important roles during the particle-water interaction processes. By normalization to shales, the 3 forms of REEs follow convex shapes according to atomic number with middle REE (Sm, Eu, and Tb) enrichment, while light REE and heavy REE are depleted. 相似文献
11.
以深港西部通道填海区淤泥为研究对象,研究了重金属的化学形态特征,分析了填海工程活动带来的填海区地下水物理化学条件变化对重金属各个形态的影响。结果表明:除残留态外,填海区重金属存在形态主要为铁锰结合态、碳酸盐结合态和硫化物及有机结合态,其中,Pb和Ni以铁锰氧化物结合态和碳酸盐结合态为主,Cu以碳酸盐结合态和有机结合态为主,Zn以有机结合态和铁锰氧化物结合态为主,而Cd则以碳酸盐结合态为主。各金属在深港西部通道填海区淤泥的潜在迁移能力序列如下:Pb(39.68%)>Cu(31.59%)>Zn(20.49%)>Cd(12.80%)>Ni(10.98%)。 相似文献
12.
Arie Nissenbaum 《Geochimica et cosmochimica acta》1979,43(12):1973-1978
The phosphorus content of marine humic acids (HA) is in the range of 0.1–0.2%. The C/P ratios of the HA are 300 to 400. Marine fulvic acids (FA) contain 0.4–0.8% P and have C/P ratios of 80 to 100. High molecular weight organic matter dissolved in pore waters (DOM) contains 0.5% P and has C/P of 90. The data suggest that during the formation sequence: Plankton → DOM → FA → HA → Kerogen, phosphorus is lost, mainly in the FA → HA (and possibly also in the HA → Kerogen) step. Diagenesis of sedimentary humic acids is accompanied by loss of phosphorus (as well as of nitrogen) to form HA with C/P ratios of 1000.Soil humic substances resemble marine humates in P content (0.3%) and soil FA's are about three to fivefold enriched in P relative to HA. C/P ratios are lower in soil HA (ca. 200) as compared with marine HA. Humic acids from diagenetic products such as peat and lignite are highly depleted in P. Rough calculations indicate that humate bound P may account for 20–50% of the organic phosphorus reservoir in sediments. The chemical speciation of this P is unknown, but lack of correlation with ash, Fe, Ca or Al content (in marine humates, at least) indicates that it is organically bound. 相似文献
13.
Depositional environment of mudflats and mangroves and bioavailability of selected metals within mudflats in a tropical estuary 总被引：1，自引：1，他引：0
M. C. Fernandes G. N. Nayak A. Pande S. P. Volvoikar D. R. G. Dessai 《Environmental Earth Sciences》2014,72(6):1861-1875
Four sediment cores representing adjacent mudflat and mangrove sub-environments of middle estuary (Shastri) were analyzed for sand, silt, clay, and organic carbon. Total metal concentration of iron (Fe), manganese (Mn), nickel (Ni), zinc (Zn), chromium (Cr), copper (Cu), cobalt (Co), and lead (Pb) and chemical speciation of Fe, Mn, and Co on selected samples was also carried out on mudflat cores. The sediments in the upper middle estuary were found to be deposited under highly varying hydrodynamic energy conditions; whereas lower middle estuary experienced relatively stable hydrodynamic energy conditions with time. The tributary joining the river near the upper middle estuary is found to be responsible for the addition of enhanced organic carbon and metal concentrations. Speciation study indicated Fe and Co are from natural lithogenic origin while Mn is derived from anthropogenic sources. Higher Mn and Co than apparent effects threshold can pose a high risk of toxicity to organisms associated with these sediments. 相似文献
14.
Daniel G. Strawn Patrick Hickey Andrew Knudsen Leslie Baker 《Environmental Geology》2007,52(1):109-122
To remediate Pb contaminated soils it is proposed that phosphorus can be amended to the soils to transform the Pb into poorly
soluble Pb-phosphate mineral phases. However, remediation strategies must account for variable Pb speciation and site-specific
factors. In this study soil mineralogy and Pb speciation in soils from P-amended field trials at sites within the Coeur d’Alene
River Basin in Idaho, USA were investigated. The soils are contaminated from mining activities and are enriched with Fe and
Mn. Selective extraction of the soils indicated that the Fe oxides are poorly crystalline. XRD of the soil clay size fractions
identified quartz, muscovite, kaolinite, siderite, lepidocrocite, and chlorite minerals. Amendment with P fertilizer dissolved
the siderite. No Pb–phosphate minerals were detected by XRD. Electron microprobe analysis showed direct correlations between
Pb, Fe, and Mn in the unamended soils, and negative correlations between Pb and Si. Lead and Mn were strongly correlated.
In the amended soils Fe and P were strongly correlated. Results indicate that the Pb is associated with poorly crystalline
Fe and Mn oxides, and that added P is primarily associated with Fe oxide phases. Comparisons of pore water Pb concentrations
with chloropyromorphite and plumbogummite solubility suggest that in the phosphate-amended soils the pore waters are undersaturated
in these phases, whereas several of the control soil pore waters were oversaturated, indicating the added phosphate suppressed
the Pb solubility. Results from this research provide insight into the geochemistry occurring in the P-remediated soils that
will help in making management and remediation decisions. 相似文献
15.
Assessment of the geochemical reactivity of Fe-DOM complexes in wetland sediment pore waters using a nitroaromatic probe compound 总被引：1，自引：0，他引：1
J. Alexandra Hakala Yu-Ping Chin Sheela G. Agrawal 《Geochimica et cosmochimica acta》2009,73(5):1382-6822
The reductive capacity of Fe(II) present in anoxic sediment pore waters affects biogeochemically significant processes that occur in these environments, such as metal speciation, mineral solubility, nutrient bioavailability, and the transformation of anthropogenic organic compounds. We studied the reduction of pentachloronitrobenzene (PCNB) in natural pore waters to elucidate the reductive capacity of Fe(II) complexes, and monitored the redox-active species responsible for the observed kinetics. Differential pulse polarography (DPP) scans of sediment pore waters from a coastal Lake Erie wetland (Old Woman Creek National Estuarine Research Reserve, Huron, OH) revealed an increase in both Fe(III)-organic and Fe(II) species to a depth of ∼30 cm below the sediment-water interface. Concentrations of dissolved organic matter (DOM) in pore waters increased while pH decreased with depth. We found that Fe(II) was necessary for rapid PCNB reduction (<24 h), and observed faster reduction with increased pH. PCNB reduction in preserved pore waters (acidified to pH 2.5 after pore water extraction and raised to the native pH (6.7-7.6) prior to reaction) was similar to that observed in a model system containing Fe(II) and fulvic acid isolated from this site. Conversely, PCNB reduction in unaltered pore water was significantly slower than that observed in preserved pore water, indicating that the Fe(II) speciation and its reductive capacity differed. DPP scans of pore waters used for kinetic studies confirmed that pH-adjustment affected FeT speciation in the pore waters, as the Fe(III)-DOM peak current was lowered or disappeared completely in the preserved pore water samples. These data show that pH-adjustment of pore waters presumably alters both their complexation chemistry and reactivity towards PCNB, and shows how small changes in Fe complexation can potentially affect redox chemistry in anoxic environments. Our results also show that reactive organic Fe(II) complexes are naturally present in wetland sediment pore waters, and that these species are potentially important mediators of Fe(II)/Fe(III) redox biogeochemistry in anoxic sedimentary environments. 相似文献
16.
YUAN Xuyin DENG Xu SHEN Zhiyong GAO Yun 《中国地球化学学报》2007,26(4):384-393
The species of Cu, Pb, Zn, Cd and Cr in sediments of the Taihu Lake, China, have been analyzed using the sequential chemical extraction method. Variations in the chemical fractions of these metals and their geographic distributions have also been studied. For all five metals, the residual fraction is highest but the exchangeable fraction is lowest among all the fractions. Compared to other metals, Cd has the highest percentage in the exchangeable fraction, and Cr is associated mainly with the residual fraction. Cu in the organic fraction and Pb in the Fe-Mn fraction are the important species, whereas the lowest percentages are found for Cd in the organic fraction, Cu in the Fe-Mn oxide fraction and Pb in the carbonate fraction. With respect to spatial differences, the total contents in the non-residual fractions of the metals in bay sediments are found to be higher than those in other sediments. The fractions of Cd, Cu and Cr showed significant variations in different regions. The fractions of Pb and Zn, however, did not show significant variations in spatial distribution, suggesting different amounts and different paths of anthropogenic input for the metals. Comparisons of the metal speciation indicated that Cd might be the most bioavailable metal, followed by Pb. 相似文献
17.
恬矿库周围土壤中重金属存在形态特征研究 总被引：48，自引：4，他引：44
通过对大冶铜绿山铜铁矿尾矿库周围土壤中重金属形态分析实验,研究了重金属各种形态在土壤中的分布特征。由对比实验可知,尾矿库周围土壤中Ｃｕ、Ｐｂ、Ｚｎ、Ｃｄ等重金属含量都显著地高于对照样品,书经受到重金属的严重污染。土壤中重金属形态分布征为：ｗ（Ｃｒ、Ｚｎ、Ｆｅ）;可变换态〈碳酸盐态〈有机态〈铁锰氧化态〈残渣态;ｗ（Ｃｕ、Ｐｂ）：可变换态〈碳酸盐态〈有机态〈残渣态〈铁锰氧化态;ｗ（Ｃｄ）：残渣态,有机 相似文献
18.
按Tessier连续浸提法对德安锑矿区土壤样品进行了分析,得出锑的存在状态主要以残渣态为主,其次是Fe/Mn结合态,有机/硫化物结合态和碳酸盐结合态,可交换态和水溶态占的比率最小。矿区土壤中锑生物可利用态锑占0.52%~3.51%,其浓度一般在1.78~17.48μg/g,中等可利用态占1.04%~5.56%,生物难利用态锑的浓度占92.1%~98.4%。 相似文献
19.
Utilizing a sequential extraction technique this study provides the first quantitative analysis on the abundance of sedimentary
phosphorus and its partitioning between chemically distinguishable phases in sediments of the Bering Sea, the Chukchi Sea
and the Mackenzie River Delta in the western Arctic Ocean. Total sedimentary phosphorus (TSP) was fractionated into five operationally
defined phases: (1) adsorbed inorganic and exchangeable organic phosphorus, (2) Fe-bound inorganic phosphorus, (3) authigenic
carbonate fluorapatite, biogenic apatite and calcium carbonate-bound inorganic and organic phosphorus, (4) detrital apatite,
and (5) refractory organic phosphorus. TSP concentrations in surface sediments increased from the Chukchi Sea (18 μmol g−1 of dried sediments) to the Bering Sea (22 μmol g−1) and to the Mackenzie River Delta (29 μmol g−1). Among the five pools, detrital apatite phosphorus of igneous or metamorphic origin represents the largest fraction (~43%)
of TSP. The second largest pool is the authigenic carbonate fluorapatite, biogenic apatite as well as CaCO3 associated phosphorus (~24% of TSP), followed by the Fe-bound inorganic phosphorus, representing ~20% of TSP. The refractory
organic P accounts for ~10% of TSP and the readily exchangeable adsorbed P accounts for only 3.5% of TSP. Inorganic phosphorus
dominates all of phosphorus pools, accounting for an average of 87% of the TSP. Relatively high sedimentary organic carbon
and total nitrogen contents and low δ13C values in the Mackenzie River Delta together with the dominance of detrital apatite in the TSP demonstrate the importance
of riverine inputs in governing the abundance and speciation of sedimentary phosphorus in the Arctic coastal sediments. 相似文献
20.
Vertical variation of phosphorus forms in surface sediments from Wuli Bay, Taihu Lake, China 总被引：1，自引：0，他引：1
1IntroductionPhosphorus,an essential nutrient for the primaryproductivity in freshwater systems,is an important fac-tor controlling lacustrine eutrophication.Although ex-ternal input of phosphorus has been assumed as the vi-tal responsibility for the eutrophication of lakes(ZhuJun et al.,2005),the remobilization of phosphorus insediments has a distinct influence on it as well(Bostr m et al.,1982).The concentrations of totalphosphorus(Ptotal)in the sediments are often related tothe trophic st… 相似文献